Method and device for introducing for mixing a first liquid into a second liquid

ABSTRACT

Method and device for introducing for mixing a first liquid into a second liquid for use in automated apparatus for the quantitative analysis of a treated substance. The device includes a body defining an elongated passageway portion. One end of the passageway portion provides an inlet for the first liquid, and the other end provides an outlet for the first liquid to which the second liquid has been admixed in the passageway portion. A tube, carrying the second liquid in a countercurrent direction, has a discharge end directed axially within the passageway portion and spaced from the wall structure thereof for mixing impact of the two liquids in substantially the central area of the passageway portion, and so arranged that the intermixed liquids flow around the last-mentioned tube end substantially throughout the cross section of the cavity between the tube and the passageway portion before exiting from the last-mentioned portion.

United States Patent [191 Heimann et all.

[54] METHOD AND DEVICE FOR INTRODUCING FOR MIXING A FIRST LIQUID INTO ASECOND LIQUID [75] Inventors: Richard H. Heimann,

Aaron Kassel, Tarrytown; Donald F. Kopelman, New York, all of N.Y.

[73] Assignee: Technicon Instruments Corporation,

Tarrington, N.Y.

[22] Filed: Apr. 14, 1971 [21] Appl.No.: 133,989

137/604, 73/423 A [51] Int. Cl. ..Fl7d 1/08, Fl6k 19/00 [58] Field ofSearch ..137/1, 13, 154, 602,

137/604; 23/230 A, 253 A; 73/53, 423 A; 259/4; 356/179, 181

2,933,293 4/1960 Ferrari, Jr. ..259/4 Flushing;

[451 Apr. 10, 1973 8/1970 Hrdina ..137/154 X Primary Examiner-Robert G.Nilson Attorney-Tedesco & Rockwell [57 ABSTRACT Method and device forintroducing for mixing a first liquid into a second liquid for use inautomated apparatus for the quantitative analysis of a treatedsubstance. The device includes a body defining an elongated passagewayportion. One end of the passageway portion provides an inlet for thefirst liquid, and the other end provides an outlet for the first liquidto which the second liquid has been admixed in the passageway portion. Atube, carrying the second liquid in a countercurrent direction, has adischarge end directed axially within the passageway portion and spacedfrom the wall structure thereof for mixing impact of the two liquids insubstantially the central area of the passageway portion, and soarranged that the intermixed liquids flow around the last-mentioned tubeend substantially throughout the cross section of the cavity between thetube and the passageway portion before exiting from the last-mentionedportion.

10 Claims, 3 Drawing Figures PATENTEDAFRIOIQYS 3,726,297

FIG. 1 PRIOR ART INVENTORS RICHARD H. HEIMANN AARON KASSEL DONALD F.KOPELMAN ATTORNEY METHOD AND DEVICE FOR INTRODUCING FOR MIXING A FIRSTLIQUID INTO A SECOND LIQUID BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to a method and device for introducingfor mixing a first liquid into a second liquid for use in automatedapparatus for the quantitative wet-chemical analysis of a treatedsubstance.

2. Prior Art In analysis systems of this kind, a flowing stream ofsample liquid, which stream may be a continuous monitoring stream, or astream of sequential liquid samples, may be continuously mixed in apredetermined propor tion with one or more reagents, and otherwiseprocessed to provide a color reaction, for example, the optical densityof which at a particular wavelength is responsive to the concentrationof a constituent of interest in the original sample. Such a system isdisclosed in Skeggs U.S. Pat. No. 2,797,149 issued June 25, I957. Skeggset al. U.S. Pat. No. 3,241,432 issued Mar. 22, 1966 shows and describesapparatus for performing multiple different tests on each of a series ofsamples.

Customarily, the flowing stream of sample plus reagent and, perhaps,diluent is divided into sequential segments, each succeeding segment ofsample plus additions being spaced from the preceding segment by asegment of gas or other immiscible fluid. Each segment of sample plusany addition thereto is then mixed, as in a mixing coil, as it flowsalong in the stream such as shown and described in Ferrari, Jr. U.S.Pat. No. 2,933,293 issued Apr. 19, 1960. In todays systems it is oftennecessary to intermix other liquids such as two or more reagents or adiluent and a reagent, for example.

Prior to being intermixed, the streams of sample and reagent, forexample, are supplied in predetermined proportions to a junction as by aperistaltic proportiom ing pump such as shown and described inBilichniansky et al U.S. Pat. No. 3,425,357 issued Feb. 4, I969. Thestream of sample, which may be segmented, may be supplied from aturntable supporting a series of liquid samples in cups as shown anddescribed in Skeggs U.S. Pat. No. 2,879,141 issued Mar. 24, 1959.

Today, in many hospitals, for example, there is a need for automatedquantitative analysis apparatus which will accurately and speedilyperform a large number of different tests on each one of a large numberof different samples, as in the analysis of human blood samples. It isdesired that up to l2 different tests or more be made on such apparatuson each of 60 or more different samples within a period of an hour. Suchdesirable systems must inherently employ miniscule amounts of eachsample for each test and a correspond- -ing volume of reagent. The speedof mixing liquids together is critical to the fast performance of anysuch apparatus which carries out the tests and then records the results.

It is often desired to intermix two liquids in a stream prior to theintroduction of a third liquid downstream and upstream from a mixer suchas a mixing coil. It may also be desirable to maintain the points ofconfluence of the last-mentioned liquids at a short distance apart in astream for fast execution of a test by such apparatus. It is desirablethat the first two liquids, which may react with one another, mix andcommence any reaction therebetween as soon as possible after theconfluence of the streams of the first and second liquids, and for thisto occur it is necessary that the two streams be intermixedsubstantially thoroughly at the point of confluence.

Heretofore, such instantaneous substantially thorough mixing at theconfluence of such streams has not taken place in analytical apparatussuch as described as far as is known. It has been the practice to bringthe confluence of two such streams together at approximate right anglesand to then flow the resultant stream in the same direction as thedirection of inflow of one of the aforementioned converging streams.When a liquid to be admixed in this fashion in another liquid isintroduced in this manner it tends to flow along that part of the wallstructure of the conduit in which it was introduced and not mixthoroughly with the other liquid unless or until the two liquids arepassed through a mixer such as a coil. Of course, the flow of the streamthrough one or more mixing coils or even through a static mixer, such asshown and described in Dannewitz et al. U.S. Pat. application Ser. No.60,474, filed Aug. 3, I970 and assigned to the same assignee as theinstant invention, delays the transit of the stream to the analysisstation of the apparatus.

SUMMARY OF THE INVENTION One object of the invention is to provide animproved method and device for introducing for mixing one liquid intoanother liquid in a manner to cause impact of one on the other for amixing effect for use in automated apparatus for the quantitativeanalysis of a treated substance. It is within the purview of theinvention that one of the liquids may be segmented as by gas bubbles andthat the other liquid may be added to the first liquid according to thetechnique without disturbing the segmentation of the stream.

In accordance with the invention, there is further provided a bodydefining a walled, elongated fluid passageway portion having an inletend for a first liquid supplied at a substantially constant flow rateand having an outlet end. A tube is provided having an inlet for asecond liquid at a substantially constant but slower flow rate and at apressure in excess of the pressure of the inflowing first liquid. Thetube, which carries the second liquid for admixture with the firstliquid, has a discharge end portion directed axially within theaforementioned passageway portion intermediate the inlet and the outletof the latter and spaced from the wall structure thereof. The dischargeend portion of the tube extends in a countercurrent direction to thedirection of flow of the first liquid for impact mixing of the liquidsin the aforementioned passageway portion and flow of the mixture aroundthe tube discharge end portion prior to exit of the mixture from theaforesaid passageway portion outlet.

BRIEF DESCRIPTION OF THE DRAWING lustrated somewhat diagramatically forintroducing for.

mixing a first liquid with a second liquid, embodying the invention; and

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the aforementionedprior art technique of bringing together at a junction two streams ofliquid to be subsequently mixed there is shown in FIG. 1 by way ofexample a block of any suitable material for forming passageways thereinfor fluids which may be corrosive. The block may be structured of amaterial sold under the trademark Lucite, for example. The block 10 hasa bore 11 therethrough and a smaller bore 12 extends through one face ofthe block into communication with the bore 1 1.

A stream of liquid is caused to flow in a conventional manner throughthe bore 11 in the direction of the arrows shown in the last-mentionedview. This liquid is shown as having segments 13 separated from oneanother by segments 14 of an immiscible fluid which may be a gas. Thesegments 14 are inert and may take the form of air bubbles, for example,introduced in a conventional manner into the stream prior tointroduction of the stream into the bore 11 and of a size to completelyocclude the bore. The segmented stream may be considered by way ofexample as a stream of reagent liquid to which another liquid is to beadmixed subsequent to introduction into the bore 11 through the bore 12.

As shown in FIG. 1, a liquid suitably supplied for laminar flow entersthe bore 11 from the bore 12 which liquid, indicated at 15, may beconsidered for purposes of illustration as a sample. It will be seen inthis view that the liquid 15 introduced into the bore 11 in which thesegmented reagent flow tends to lie along the area of the point of itsintroduction into the bore 11 as it flows with the reagent stream towardthe aforementioned analysis station. In other words, the two streams donot tend to mix as clearly shown in this view, and if the two streamsare carried in a common conduit in a straight line downstream from theblock 10 for a distance of a foot or more the reagent stream of liquidand the admixed sample stream tend to remain in substantially the sameseparated condition as shown in FIG. 1. Of course, some liquids mix morereadily than others.

This process observed on closed circuit television, has indicated thatthe sample liquid 15 tends to pile up to a small extent on the leadingedges of the bubbles 14 as shown in FIG. 1. It will be understood thatthe passageways l1 and 12 shown in FIG. 1 may be structured of lengthsof glass tubing if desired rather than formed in a block as shown. 4

In the device shown in FIGS. 2 and 3 embodying the invention there isprovided a block 16 similar to the block 10 and having a passagewayportion, indicated generally at 18, extending therethrough having aninlet end 20 and an outlet end 21. A liquid such as a reagent, forexample, is caused to flow in a conventional manner into the inlet 20and out the outlet 21. The direction of flow is indicated by the arrows.This liquid may be segmented as shown by segments of an immiscible fluidsuch as inert gas bubbles 22. Such bubbles may be formed of air ornitrogen for example. The segments 22 may be formed of a liquidimmiscible with the reagent, provided that such segments do not have atendency to break up while passing through the passageway portion 18 ina manner to be described hereinafter. It is also to be understood thatthe laminar stream entering the inlet 20 may be unsegmented within thepurview of the invention and the stream may be formed of a liquid otherthan a reagent such as a diluent or a sample for example.

A tube 24 constructed of a non-corrosive material extends into thepassageway portion 18 to carry a liquid to be admixed with the liquidentering the inlet 20 and directed by the tube in a countercurrentdirection to the stream entering the last-mentioned inlet so that impactis created between the liquid flowed through the tube 24 and the liquidwhich has entered the inlet 20. This impact creates a turbulence in therespective liquids which effects substantially thorough mixing of theliquids at this point in their travel and prior to their combined exitthrough outlet 21.

The liquid, which may be supplied to the tube 24 in any conventionalmanner for admixture with the liquid flowing between the inlet 20 andthe outlet 21, may be a sample, for example, or may be a reagent or adiluent. Like the stream entering the inlet 20, the liquid flowing inthe tube 24 may be segmented if desired, although, if this is the case,segments in the liquid traveling in the tube 24 and discharged therefromwill disturb the segmentation pattern formed by the segments 22 in theliquid entering the inlet 20. Of course, the segmentation of the liquidentering the inlet 20 may be omitted as previously indicated.

At least primarily for the purpose of ease of assembly of the tube 24 inthe passageway portion 18, the passageway portion is elbowed as shown toprovide arm parts 26 and 28. The tube 14 is inserted into the arm part26 with which the inlet 20 is associated through the elbow of thepassageway portion 18 as shown in FIG. 2. The tube 24 has an inlet, asat 30, and an outlet or discharge end 32. As shown, the discharge endportion of the tube 24 is spaced from the wall structure of thepassageway portion 18 and may be concentric therewith. It is deemedunnecessary that the tube 24 be absolutely concentric. Suchconcentricity appears to provide for better mixing of the two liquidsbut it may be sufficient that the tube extend in the direction showninto the passageway portion 18 only axially and in spaced relation fromthe wall structure of the portion 18.

It should be noted that the outer surface portion of the tube 24extending within the arm part 26 and the wall structure of the arm part26 form therebetween a cavity or chamber in which the flow of the liquidinflowing through the inlet 20 is restricted. This restriction creates afaster flow of fluids in this area toward the outlet 21, and thisenhances the mixing effect between the liquids.

Tube 24 has a tight fit within a bore 34 of the block, and the bore 34is counter-bored, as shown in FIG. 2, to receive a suitable sealinggasket 36 around the tube. The tube 24 extends a sufficient distanceinto the arm part 26 of the passageway portion to permit the longestanticipated stream segment or bubble 22 to be completely deformed aroundthe tube 24 before the bubble reaches the elbow and must pass from itsembracing position around the tube 24 into the arm part 28 of thepassageway portion, so as to effectively tend to prevent the breakup ofsuch bubble.

The arm parts 26 and 28 of the passageway portion are illustrated, byway of example only, in right angular relationship to one another withthe junction being formed on a radius, as at 38. Because of the elbowedform of the passageway portion 18, the arm part 28 is restricted, as at40, in the region adjoining the elbow to effectively tend to prevent thebreakup of a bubble as it passes through the elbow. It is believed madeclear that the gas bubbles 22 effectively maintain the segmentationpattern of the stream isolating liquid segments therebetween while alsoserving to cleanse the conduit walls as they pass through the device. Itshould be made clear in this connection that a bubble passing throughthe passageway portion 18 and deformed by the end 32 of the tube 24 mayembrace the tube 24 and substantially encircle it without completelydoing so. it is believed that at least rarely does such a deformedbubble form a true annulus around the tube 24.

The cross section of the tube is preferably round but it could bestructured as a square, for example, which would indicate, for bestperformance, that the cross section of the passageway portion 18, whichis preferably the same as that of the tube, would also be square.

For illustrative purposes only, the diameter of the passageway portion18, except for the restriction 40, formed therein may be in theneighborhood of 0.039 inch. The restriction 40 may be in theneighborhood of 0.031 inch in diameter. The tube 24 may have an outerdiameter of 0.024 inch and an inner diameter of 0.016 inch for example.

It is believed made clear from the foregoing that the passageway portion18 could well be provided by glass tubing instead of being formed in ablock. As shown, the inlet end 30 of the tube 24 extends a distance fromthe block 16 for suitable connection to a conduit for the inflow ofliquid in the tube 24 as aforesaid. it should be noted that when thisliquid is discharged from the end 32 of the tube to impact liquidflowing in the op posite direction into the passageway portion 18through the inlet 20, the mixing action is such that liquid from thedischarge end 32 of the tube tends to mix with the other liquid entirelyaround the tube 32 as it reverses its direction and flows toward theoutlet 21. In this manner, a good mixing action is obtained in thecavity formed between the tube 24 and the wall structure of thepassageway portion 18.

It will be evident that the liquid supplied to the inlet 20 should beprovided at a substantially constant flow rate, and that the liquidsupplied to the inlet 30 of the tube should be provided at a constantbut slower flow rate and at a pressure in excess of the pressure of theinflowing liquid at the inlet 20. For illustrative'purposes only, theinflow at the inlet 20 may be at the rate of 0.32 ml/min. of liquid plus0.1 ml/min. of air in the form of gas bubbles which may numberapproximately 60/min; The inflow through the inlet 30 of the tube may be0.03 rnl/min. ofliquid.

While several embodiments of the invention have been described, it willbe apparent to those versed in the art that the method and device forintroducing for mixing a first liquid into a second liquid for use inautomated apparatus for quantitative analysis of a treated substance maytake other forms and are susceptible of various changes withoutdeparting from the principles of the invention.

What is claimed is:

l. A device for use in a flowing stream of a quantitative wet-chemicalanalysis apparatus, for introducing for mixing a first liquid into agas-segmented second liquid having a segmentation pattern, comprising: abody defining a walled generally L-shaped fluid passageway portionhaving an inlet end for the second liquid supplied at a substantiallyconstant laminar flow rate and having an outlet end, said passagewayportion being elbowed and the elbow being formed on a radius, and a tubehaving an inlet for the first liquid at a substantially constant butslower flow rate and under pressure in excess of the pressure of theinflowing second liquid, said tube, extending into and beyond saidelbow, in the central region of said passageway portion, carrying saidfirst liquid for admixture to said second liquid and having a dischargeend portion directed in a countercurrent direction to the direction offlow of said second liquid for mixing of the liquid in said passagewayportion prior to the exit in laminar flow of the mixture from saidpassageway portion outlet, without destruction of said segmentationpattern.

2. A device as defined in claim 1 wherein, said tube and said passagewayportion define therebetween an annular chamber forming a restriction insaid passageway portion to create a faster flow of said liquids, therebyenhancing the mixing effect of said liquids.

3. A device as defined in claim 1 wherein, said passageway portion hasin proximity to said elbow a restriction to prevent destruction of saidsegmentation pattern.

4. A method for use in quantitative wet-chemical analysis of a sample,for introducing for mixing a first liquid into a gas segmented secondliquid having a segmentation pattern, comprising the steps of: flowingsaid second liquid at a substantially constant laminar flow rate into aninlet end of an elongated passageway portion of a first conduit whichportion has an outlet end, flowing said first liquid in a second conduitat a substantially constant but slower laminar flow rate and at apressure in excess of the pressure of the first liquid, and

introducing the second liquid from the second conduit into the centralregion of the first liquid stream in a countercurrent direction theretointermediate said inlet and said outlet of said passageway portion, sothat said liquids mix with one another in some turbulence withoutdestroying said segmentation pattern prior to exiting from saidpassageway portion outlet in laminar flow.

5. The method as defined in claim 4, further including the step ofrestricting the flow of the first liquid immediately downstream from thepoint of said introduction of the first liquid, thereby creating afaster flow in this region and enhancing mixing of the liquids.

6. The method as defined in claim 4, wherein, said first liquid is areagent.

7. The method as defined in claim 4 wherein, said first liquid is asample.

8. The method as defined in claim 4 wherein said first liquid is adiluent.

9. The method as defined in claim 4 wherein said second liquid is asample.

10. The method as defined in claim 4 wherein said first and secondliquids are reagents.

1. A device for use in a flowing stream of a quantitative wetchemicalanalysis apparatus, for introducing for mixing a first liquid into agas-segmented second liquid having a segmentation pattern, comprising: abody defining a walled generally L-shaped fluid passageway portionhaving an inlet end for the second liquid supplied at a substantiallyconstant laminar flow rate and having an outlet end, said passagewayportion being elbowed and the elbow being formed on a radius, and a tubehaving an inlet for the first liquid at a substantially constant butslower flow rate and under pressure in excess of the pressure of theinflowing second liquid, said tube, extending into and beyond saidelbow, in the central region of said passageway portion, carrying saidfirst liquid for admixture to said second liquid and having a dischargeend portion directed in a countercurrent direction to the direction offlow of said second liquid for mixing of the liquid in said passagewayportion prior to the exit in laminar flow of the mixture from saidpassageway portion outlet, without destruction of said segmentationpattern.
 2. A device as defined in claim 1 wherein, said tube and saidpassageway portion define therebetween an annular chamber forming arestriction in said passageway portion to create a faster flow of saidliquids, thereby enhancing the mixing effect of said liquids.
 3. Adevice as defined in claim 1 wherein, saiD passageway portion has inproximity to said elbow a restriction to prevent destruction of saidsegmentation pattern.
 4. A method for use in quantitative wet-chemicalanalysis of a sample, for introducing for mixing a first liquid into agas segmented second liquid having a segmentation pattern, comprisingthe steps of: flowing said second liquid at a substantially constantlaminar flow rate into an inlet end of an elongated passageway portionof a first conduit which portion has an outlet end, flowing said firstliquid in a second conduit at a substantially constant but slowerlaminar flow rate and at a pressure in excess of the pressure of thefirst liquid, and introducing the second liquid from the second conduitinto the central region of the first liquid stream in a countercurrentdirection thereto intermediate said inlet and said outlet of saidpassageway portion, so that said liquids mix with one another in someturbulence without destroying said segmentation pattern prior to exitingfrom said passageway portion outlet in laminar flow.
 5. The method asdefined in claim 4, further including the step of restricting the flowof the first liquid immediately downstream from the point of saidintroduction of the first liquid, thereby creating a faster flow in thisregion and enhancing mixing of the liquids.
 6. The method as defined inclaim 4, wherein, said first liquid is a reagent.
 7. The method asdefined in claim 4 wherein, said first liquid is a sample.
 8. The methodas defined in claim 4 wherein said first liquid is a diluent.
 9. Themethod as defined in claim 4 wherein said second liquid is a sample. 10.The method as defined in claim 4 wherein said first and second liquidsare reagents.